Leading article: Paris for President

We are accustomed to US presidential campaigns turning nasty. But campaigns that turn humorous, even witty? In using images of the supposedly airhead celebrities Paris Hilton and Britney Spears to cast Barack Obama as narcissistic and content-free, John McCain was taking the gloves off with time-honoured American ruthlessness. He was doubtless waiting for his opponent to hit back in kind.

What he surely did not bargain for was sarcasm, in the form of a spoof ad direct from the sun lounger of Ms Hilton. Swimsuited and occasionally distracted by her magazine, she observes that, as she now appears to be running for President, she has a few things she would like to say to "that wrinkly, white-haired guy". Within minutes, the "ad" was all over the internet – you can watch it, and enjoy it, yourself.

But if the McCain team thought Hilton – always more than a pretty face – was "ditzy", they were sorely, and perhaps expensively, mistaken. Her clip of the "super-old" senator may prove more than a diverting footnote to the real campaign.